Red blood cells Flashcards
what 2 things do HSCs have the ability to do
self renew- some daughter cells remain as HSCs , pool of HSC is non depleting
differentiate to mature progeny
which 3 places does haematopoiesis occur in embryonic devel and during which weeks of gestation
Yolk Sac 3 weeks, HSC is generated
Liver 6-8 weeks, HSC is maintained and expanded
Bone marrow in pelvis femur and sternum (for adult) 10 weeks, HSC begins haematopoietic activity
what type of molecule haematopoietic growth factors
what do they do
glycoprotein hormones that bind to cell surface receptor
regulate function of mature red blood cells
regulate the proliferation and differentiation of red blood cells
what are the growth factors for:
- red blood cell
- granulocyte
- monocyte
erythropoietin
G- CSF and cytokines
G-M CSF and cytokines
4 stages of the differentiation of red blood cells
myeloid progenitor
pro erythroblast
erythroblast
erythrocyte
- What are the 4 things required for erythropoiesis?
- What causes microcytic anaemia?
- What causes macrocytic anaemia?
Folate, B12, Iron, Erythropoietin
iron deficiency
B12 and folate deficiency
- What is erythropoietin and when would it stimulate bone marrow produce RBCs?
- What are the major functions of iron?
glycoprotein that regulates erythropoiesis
in response to hypoxia- low 02 in kidney, stimulate erythropoiesis to increase 02
transport 02 in Hb (haem iron)
Mitochondrial proteins cytochrome a,b,c for production of ATP
cytochrome P450 for hydroxylation reactions (eg drug metabolism)
- List 3 signs that may indicate a person has iron deficiency.
- What is the best absorbed form of iron
- Why is excess iron bad?
Koilonychia - spoon shaped nails
Glossitis - inflammation of tongue
Angular stomatitis - inflammation of corners of mouth
Ferrous Iron (2+)
no physiological excretion method
- What regulates the absorption of iron in the gut and what suppresses its synthesis?
- what does it do?
- what is it secreted in response to
Hepcidin, Erythropoietic activity
absorption (from stomach) and release of storage iron (from liver) is blocked by hepcidin
High storage iron
- What does non-haem iron require action of for absorption?
- What are folate and VB12 needed for?
- What does vitamin B12 bind to in the stomach during its absorption?
ascorbic acid/ vitamin C
to synthesis thymine
as they are needed to synthesis DTTP, its precursor
Intrinsic factor, the B12-IF complex binds to receptors in ileum
- Where is intrinsic factor made?
- What is pernicious anaemia?
- A lack of which foods in diet can lead to a vitamin B12 deficiency?
Gastric parietal cells
Lack of IF secretion
meat and fish
- Where does the absorption of folate take place?
- When do the requirements of folate increase?
- How long do red cells circulate for?
Duodenum
pregnancy, low RBC production eg sickle cell anaemia
120days
- Where do red cells undergo phagocytosis?
- What is released from the haem (porphyrin) ring when it is recycled?
- What is iron bound to on its way back to the bone marrow?
Spleen
Iron
Transferrin
- What does the catabolism of haem produce and where is this product excreted?
- Describe the red cell membrane
- What happens to red blood cells during hereditary spherocytosis?
Bilirubin
excreted in Bile
contains transmembrane proteins
has a lipid bilayer supported by protein cytoskeleton
These help to maintain flexibility and shape and elasticity/deformability of red blood cell
become spherical with no central pallour
- What causes these hereditary spherocytosis?
- What happens to those red blood cells?
vertical linkages are disrupted
loss of membrane without loss of cytoplasm, cell forced to round up
RBC is less flexible
haemolysis, they are prematurely removed by the spleen
